1. Field of the Invention
This invention relates to a process for separating components of an azeotrope-like mixture. More particularly, this invention relates to a process for separating hydrogen fluoride from an azeotrope-like mixture comprising hydrogen fluoride and at least one hydrofluorocarbon.
2. Description of Prior Art
Certain hydrofluoroolefins, such as 2,3,3,3-tetrafluoropropene (HFO-1234yf), are useful in a variety of applications. For example, HFO-1234yf can be used as a refrigerant, solvent, blowing agent, and the like. Hydrofluoroolefins have a relatively low Global Warming Potential (GWP) and little or no ozone depletion potential. Therefore, these compounds are environmentally friendly.
HFO-1234yf can be manufactured from 1,1,2,3-tetrachloropropene or 1,1,1,2,3-pentachloropropane using a multi-step process, such as the one described in US Publication No. 2007/0197842. One part of this process involves dehydrochlorinating 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) to form the desired HFO-1234yf. The HCFC-244bb, in turn, can be obtained by reacting 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) with a stoichiometric excess of hydrogen fluoride (HF). The excess HF in the reaction mixture optimizes the conversion of HCFO-1233xf and the selectivity of the desired HCFC-244bb product. However, due to this excess HF and limitations in the reaction's efficiency, the resulting reaction product typically contains un-reacted HCFO-1233xf as well as a significant amount of unreacted HF. Preferably, the unreacted HF is recovered from the reaction product and recycled to increase the economic efficiency of the process.